And the issue seems to be something much graver than a small group of conspiracy theorists shouting while covering their ears.

Brian Palmer, reporting for Slate, writes: “The vast majority of those who don’t vaccinate their children… represent a collective social failure. Somehow, we’re slowly losing a debate to a group of people who are spectacularly, demonstrably wrong. If we can’t beat them, we should blame ourselves.”

Palmer reached out to a wide range of pediatricians to find out how they feel about these parents, and he was surprised to encounter mostly sadness rather than anger on the part of these doctors, who often feel like they have let their patients down by not convincing them to vaccinate.

One deeply flawed, since-retracted study of 12 children made some parents fearful that there might be an association between vaccines and autism. Since then, a long list of studies involving many thousands of children have shown that this alleged link does not exist. But anti-vaxxers remain unconvinced, and while this often causes anger, it should also cause deep sadness and fear.

Most people who don’t vaccinate their children are not, Palmer says, “loud-mouthed ignoramuses who try to spread their pernicious, conspiratorial nonsense.” They’re just misinformed, distrustful, and resistant to the mountain of evidence that has proven that their fears are unsubstantiated and were based on bad science to begin with.

That’s the most tragic and terrifying thing about the anti-vaxxer movement: These parents trust their guts more than scientific studies, and that’s mostly because of fear and distrust. If science can’t win here, where the evidence is strong and clear, where will it win? And what does that say about people’s confidence in facts?

This latest measles outbreak makes clear that not only are we seeing diseases we’ve beaten creep back into the population, but we’re also witnessing a breakdown of the social contract, an alarming disbelief in science, and a failure of the basic trust required to ensure our public health.